6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yu Kuai yukuai3@huawei.com
commit 127186cfb184eaccdfe948e6da66940cfa03efc5 upstream.
THe md-linear is removed by commit 849d18e27be9 ("md: Remove deprecated CONFIG_MD_LINEAR") because it has been marked as deprecated for a long time.
However, md-linear is used widely for underlying disks with different size, sadly we didn't know this until now, and it's true useful to create partitions and assemble multiple raid and then append one to the other.
People have to use dm-linear in this case now, however, they will prefer to minimize the number of involved modules.
Fixes: 849d18e27be9 ("md: Remove deprecated CONFIG_MD_LINEAR") Cc: stable@vger.kernel.org Signed-off-by: Yu Kuai yukuai3@huawei.com Acked-by: Coly Li colyli@kernel.org Acked-by: Mike Snitzer snitzer@kernel.org Link: https://lore.kernel.org/r/20250102112841.1227111-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu song@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/Kconfig | 13 + drivers/md/Makefile | 2 drivers/md/md-autodetect.c | 8 drivers/md/md-linear.c | 354 +++++++++++++++++++++++++++++++++++++++++ drivers/md/md.c | 2 include/uapi/linux/raid/md_p.h | 2 include/uapi/linux/raid/md_u.h | 2 7 files changed, 379 insertions(+), 4 deletions(-) create mode 100644 drivers/md/md-linear.c
--- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -61,6 +61,19 @@ config MD_BITMAP_FILE various kernel APIs and can only work with files on a file system not actually sitting on the MD device.
+config MD_LINEAR + tristate "Linear (append) mode" + depends on BLK_DEV_MD + help + If you say Y here, then your multiple devices driver will be able to + use the so-called linear mode, i.e. it will combine the hard disk + partitions by simply appending one to the other. + + To compile this as a module, choose M here: the module + will be called linear. + + If unsure, say Y. + config MD_RAID0 tristate "RAID-0 (striping) mode" depends on BLK_DEV_MD --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -29,12 +29,14 @@ dm-zoned-y += dm-zoned-target.o dm-zoned
md-mod-y += md.o md-bitmap.o raid456-y += raid5.o raid5-cache.o raid5-ppl.o +linear-y += md-linear.o
# Note: link order is important. All raid personalities # and must come before md.o, as they each initialise # themselves, and md.o may use the personalities when it # auto-initialised.
+obj-$(CONFIG_MD_LINEAR) += linear.o obj-$(CONFIG_MD_RAID0) += raid0.o obj-$(CONFIG_MD_RAID1) += raid1.o obj-$(CONFIG_MD_RAID10) += raid10.o --- a/drivers/md/md-autodetect.c +++ b/drivers/md/md-autodetect.c @@ -49,6 +49,7 @@ static int md_setup_ents __initdata; * instead of just one. -- KTK * 18May2000: Added support for persistent-superblock arrays: * md=n,0,factor,fault,device-list uses RAID0 for device n + * md=n,-1,factor,fault,device-list uses LINEAR for device n * md=n,device-list reads a RAID superblock from the devices * elements in device-list are read by name_to_kdev_t so can be * a hex number or something like /dev/hda1 /dev/sdb @@ -87,7 +88,7 @@ static int __init md_setup(char *str) md_setup_ents++; switch (get_option(&str, &level)) { /* RAID level */ case 2: /* could be 0 or -1.. */ - if (level == 0) { + if (level == 0 || level == LEVEL_LINEAR) { if (get_option(&str, &factor) != 2 || /* Chunk Size */ get_option(&str, &fault) != 2) { printk(KERN_WARNING "md: Too few arguments supplied to md=.\n"); @@ -95,7 +96,10 @@ static int __init md_setup(char *str) } md_setup_args[ent].level = level; md_setup_args[ent].chunk = 1 << (factor+12); - pername = "raid0"; + if (level == LEVEL_LINEAR) + pername = "linear"; + else + pername = "raid0"; break; } fallthrough; --- /dev/null +++ b/drivers/md/md-linear.c @@ -0,0 +1,354 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * linear.c : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc + * ZYNGIER zyngier@ufr-info-p7.ibp.fr or maz@gloups.fdn.fr + */ + +#include <linux/blkdev.h> +#include <linux/raid/md_u.h> +#include <linux/seq_file.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <trace/events/block.h> +#include "md.h" + +struct dev_info { + struct md_rdev *rdev; + sector_t end_sector; +}; + +struct linear_conf { + struct rcu_head rcu; + sector_t array_sectors; + /* a copy of mddev->raid_disks */ + int raid_disks; + struct dev_info disks[] __counted_by(raid_disks); +}; + +/* + * find which device holds a particular offset + */ +static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector) +{ + int lo, mid, hi; + struct linear_conf *conf; + + lo = 0; + hi = mddev->raid_disks - 1; + conf = mddev->private; + + /* + * Binary Search + */ + + while (hi > lo) { + + mid = (hi + lo) / 2; + if (sector < conf->disks[mid].end_sector) + hi = mid; + else + lo = mid + 1; + } + + return conf->disks + lo; +} + +static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks) +{ + struct linear_conf *conf; + sector_t array_sectors; + + conf = mddev->private; + WARN_ONCE(sectors || raid_disks, + "%s does not support generic reshape\n", __func__); + array_sectors = conf->array_sectors; + + return array_sectors; +} + +static int linear_set_limits(struct mddev *mddev) +{ + struct queue_limits lim; + int err; + + md_init_stacking_limits(&lim); + lim.max_hw_sectors = mddev->chunk_sectors; + lim.max_write_zeroes_sectors = mddev->chunk_sectors; + lim.io_min = mddev->chunk_sectors << 9; + err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); + if (err) { + queue_limits_cancel_update(mddev->gendisk->queue); + return err; + } + + return queue_limits_set(mddev->gendisk->queue, &lim); +} + +static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) +{ + struct linear_conf *conf; + struct md_rdev *rdev; + int ret = -EINVAL; + int cnt; + int i; + + conf = kzalloc(struct_size(conf, disks, raid_disks), GFP_KERNEL); + if (!conf) + return ERR_PTR(-ENOMEM); + + /* + * conf->raid_disks is copy of mddev->raid_disks. The reason to + * keep a copy of mddev->raid_disks in struct linear_conf is, + * mddev->raid_disks may not be consistent with pointers number of + * conf->disks[] when it is updated in linear_add() and used to + * iterate old conf->disks[] earray in linear_congested(). + * Here conf->raid_disks is always consitent with number of + * pointers in conf->disks[] array, and mddev->private is updated + * with rcu_assign_pointer() in linear_addr(), such race can be + * avoided. + */ + conf->raid_disks = raid_disks; + + cnt = 0; + conf->array_sectors = 0; + + rdev_for_each(rdev, mddev) { + int j = rdev->raid_disk; + struct dev_info *disk = conf->disks + j; + sector_t sectors; + + if (j < 0 || j >= raid_disks || disk->rdev) { + pr_warn("md/linear:%s: disk numbering problem. Aborting!\n", + mdname(mddev)); + goto out; + } + + disk->rdev = rdev; + if (mddev->chunk_sectors) { + sectors = rdev->sectors; + sector_div(sectors, mddev->chunk_sectors); + rdev->sectors = sectors * mddev->chunk_sectors; + } + + conf->array_sectors += rdev->sectors; + cnt++; + } + if (cnt != raid_disks) { + pr_warn("md/linear:%s: not enough drives present. Aborting!\n", + mdname(mddev)); + goto out; + } + + /* + * Here we calculate the device offsets. + */ + conf->disks[0].end_sector = conf->disks[0].rdev->sectors; + + for (i = 1; i < raid_disks; i++) + conf->disks[i].end_sector = + conf->disks[i-1].end_sector + + conf->disks[i].rdev->sectors; + + if (!mddev_is_dm(mddev)) { + ret = linear_set_limits(mddev); + if (ret) + goto out; + } + + return conf; + +out: + kfree(conf); + return ERR_PTR(ret); +} + +static int linear_run(struct mddev *mddev) +{ + struct linear_conf *conf; + int ret; + + if (md_check_no_bitmap(mddev)) + return -EINVAL; + + conf = linear_conf(mddev, mddev->raid_disks); + if (IS_ERR(conf)) + return PTR_ERR(conf); + + mddev->private = conf; + md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); + + ret = md_integrity_register(mddev); + if (ret) { + kfree(conf); + mddev->private = NULL; + } + return ret; +} + +static int linear_add(struct mddev *mddev, struct md_rdev *rdev) +{ + /* Adding a drive to a linear array allows the array to grow. + * It is permitted if the new drive has a matching superblock + * already on it, with raid_disk equal to raid_disks. + * It is achieved by creating a new linear_private_data structure + * and swapping it in in-place of the current one. + * The current one is never freed until the array is stopped. + * This avoids races. + */ + struct linear_conf *newconf, *oldconf; + + if (rdev->saved_raid_disk != mddev->raid_disks) + return -EINVAL; + + rdev->raid_disk = rdev->saved_raid_disk; + rdev->saved_raid_disk = -1; + + newconf = linear_conf(mddev, mddev->raid_disks + 1); + if (!newconf) + return -ENOMEM; + + /* newconf->raid_disks already keeps a copy of * the increased + * value of mddev->raid_disks, WARN_ONCE() is just used to make + * sure of this. It is possible that oldconf is still referenced + * in linear_congested(), therefore kfree_rcu() is used to free + * oldconf until no one uses it anymore. + */ + oldconf = rcu_dereference_protected(mddev->private, + lockdep_is_held(&mddev->reconfig_mutex)); + mddev->raid_disks++; + WARN_ONCE(mddev->raid_disks != newconf->raid_disks, + "copied raid_disks doesn't match mddev->raid_disks"); + rcu_assign_pointer(mddev->private, newconf); + md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); + set_capacity_and_notify(mddev->gendisk, mddev->array_sectors); + kfree_rcu(oldconf, rcu); + return 0; +} + +static void linear_free(struct mddev *mddev, void *priv) +{ + struct linear_conf *conf = priv; + + kfree(conf); +} + +static bool linear_make_request(struct mddev *mddev, struct bio *bio) +{ + struct dev_info *tmp_dev; + sector_t start_sector, end_sector, data_offset; + sector_t bio_sector = bio->bi_iter.bi_sector; + + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) + return true; + + tmp_dev = which_dev(mddev, bio_sector); + start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; + end_sector = tmp_dev->end_sector; + data_offset = tmp_dev->rdev->data_offset; + + if (unlikely(bio_sector >= end_sector || + bio_sector < start_sector)) + goto out_of_bounds; + + if (unlikely(is_rdev_broken(tmp_dev->rdev))) { + md_error(mddev, tmp_dev->rdev); + bio_io_error(bio); + return true; + } + + if (unlikely(bio_end_sector(bio) > end_sector)) { + /* This bio crosses a device boundary, so we have to split it */ + struct bio *split = bio_split(bio, end_sector - bio_sector, + GFP_NOIO, &mddev->bio_set); + + if (IS_ERR(split)) { + bio->bi_status = errno_to_blk_status(PTR_ERR(split)); + bio_endio(bio); + return true; + } + + bio_chain(split, bio); + submit_bio_noacct(bio); + bio = split; + } + + md_account_bio(mddev, &bio); + bio_set_dev(bio, tmp_dev->rdev->bdev); + bio->bi_iter.bi_sector = bio->bi_iter.bi_sector - + start_sector + data_offset; + + if (unlikely((bio_op(bio) == REQ_OP_DISCARD) && + !bdev_max_discard_sectors(bio->bi_bdev))) { + /* Just ignore it */ + bio_endio(bio); + } else { + if (mddev->gendisk) + trace_block_bio_remap(bio, disk_devt(mddev->gendisk), + bio_sector); + mddev_check_write_zeroes(mddev, bio); + submit_bio_noacct(bio); + } + return true; + +out_of_bounds: + pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %pg: %llu sectors, offset %llu\n", + mdname(mddev), + (unsigned long long)bio->bi_iter.bi_sector, + tmp_dev->rdev->bdev, + (unsigned long long)tmp_dev->rdev->sectors, + (unsigned long long)start_sector); + bio_io_error(bio); + return true; +} + +static void linear_status(struct seq_file *seq, struct mddev *mddev) +{ + seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); +} + +static void linear_error(struct mddev *mddev, struct md_rdev *rdev) +{ + if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) { + char *md_name = mdname(mddev); + + pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n", + md_name, rdev->bdev); + } +} + +static void linear_quiesce(struct mddev *mddev, int state) +{ +} + +static struct md_personality linear_personality = { + .name = "linear", + .level = LEVEL_LINEAR, + .owner = THIS_MODULE, + .make_request = linear_make_request, + .run = linear_run, + .free = linear_free, + .status = linear_status, + .hot_add_disk = linear_add, + .size = linear_size, + .quiesce = linear_quiesce, + .error_handler = linear_error, +}; + +static int __init linear_init(void) +{ + return register_md_personality(&linear_personality); +} + +static void linear_exit(void) +{ + unregister_md_personality(&linear_personality); +} + +module_init(linear_init); +module_exit(linear_exit); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)"); +MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ +MODULE_ALIAS("md-linear"); +MODULE_ALIAS("md-level--1"); --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8124,7 +8124,7 @@ void md_error(struct mddev *mddev, struc return; mddev->pers->error_handler(mddev, rdev);
- if (mddev->pers->level == 0) + if (mddev->pers->level == 0 || mddev->pers->level == LEVEL_LINEAR) return;
if (mddev->degraded && !test_bit(MD_BROKEN, &mddev->flags)) --- a/include/uapi/linux/raid/md_p.h +++ b/include/uapi/linux/raid/md_p.h @@ -233,7 +233,7 @@ struct mdp_superblock_1 { char set_name[32]; /* set and interpreted by user-space */
__le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ - __le32 level; /* 0,1,4,5 */ + __le32 level; /* 0,1,4,5, -1 (linear) */ __le32 layout; /* only for raid5 and raid10 currently */ __le64 size; /* used size of component devices, in 512byte sectors */
--- a/include/uapi/linux/raid/md_u.h +++ b/include/uapi/linux/raid/md_u.h @@ -103,6 +103,8 @@ typedef struct mdu_array_info_s {
} mdu_array_info_t;
+#define LEVEL_LINEAR (-1) + /* we need a value for 'no level specified' and 0 * means 'raid0', so we need something else. This is * for internal use only